Apparatus for culturing of tissue cells and micro-organisms

ABSTRACT

A rotatable shaft is mounted in a housing and a plurality of culture carriers having exposed surfaces on which the respective cultures are to grow, is releasably connected with the support to extend radially from the same within the housing. A drive is provided for rotating the support or shaft.

United States Patent 1191 Miiller Dec. 9, 1975 APPARATUS FOR CULTURING0F TISSUE 3,767,535 10/1973 Havewala et al. .1 195/143 3,839,155 10/1974McAleer et al 195/127 CELLS AND MICRO-ORGANISMS [76] inventor: HansMiiller, lm Allmendli,

Erlenbach, Zurich, Switzerland 22 Filed: Aug. 13, 1973 [21] Appl. No.:388,036

[30] Foreign Application Priority Data Aug. 18, 1972 Switzerland12326/72 [52] US. Cl. 195/127; 195/142; 195/143 [51] Int. Cl. C12B 1/16[58] Field of Search 195/127, 139, 142, 143

[56] References Cited UNITED STATES PATENTS 2,996,429 8/1961 Toulmin195/142 Primary ExaminerAlvin E. Tanenholtz Attorney, Agent, orFirmMichael S. Striker [57] ABSTRACT A rotatable shaft is mounted in ahousing and a plurality of culture carriers having exposed surfaces onwhich the respective cultures are to grow, is releasably connected withthe support to extend radially from the same within the housing. A driveis provided for rotating the support or shaft.

11 Claims, 6 Drawing Figures 7 3 12 20 k/z L l .:;::::E L

US. Patent Dec. 9, 1975 Sheet 1 of2 3,925,165

F/GZZ U.S. Patent Dec. 9, 1975 Sheet 2 of2 3,925,165

FIG. 3B I APPARATUS FOR CULTURING OF TISSUE CELLS AND MICRO-ORGANISMSBACKGROUND OF THE INVENTION The present invention relates to anapparatus for culturing of tissue cells and micro-organisms in general,and more particularly to an apparatus of this type wherein the carrierson which the cultures are to be grown, can be rotated.

It is well known that in certain circumstances a free growth of cellsmust not be permitted in culture-growing arrangements, because this canlead to an undesired deterioration of the cell structure. For thisreason the prior art has developed the concept of growing cells, whichmay for instance be isolated out of a tissue and intended for themanufacture of vaccines, on a rigid carrier having an exposed surface onwhich the cells form a monolayer. If large amounts of vaccines are to beproduced, then large surface areas must be provided on which the cellsare to grow, that is to be cultured. These surfaces areas must beuniformly contacted with nutrient medium and with certain gases,particularly with oxygen in order to pennit proper growth of the cells.

Apparatus of this type is already known in the art. Thus, it is known toprovide an apparatus having a plurality of plates which are arranged oneabove the other and on which the culture medium is to be grown. It isalso known to provide an apparatus having horizontal tubes which aremounted on vertical rotatable plates in order to facilitate the movementof liquid and gases. More recently an improved type of apparatus hasbeen proposed, which is not only more effective but also smaller thanthose known from the previous art, wherein the carrier is configuratedas a spiral element of synthetic plastic material, enamelled metal orglass. These materials have been found to be the most advantageous forthe growth of cultures.

All of the prior-art constructions have advantages, but all of them arenot entirely satisfactory in some respects. Thus, the type of apparatushaving the vertically spaced horizontal plates presents problems withsupplying the gas, because if gas is admitted below the level of liquidin the housing wherein the vertically spaced plates are located, foamwill develop in the nu trient medium and this in turn disadvantageouslyinfluences the growth of the cell culture. The result of this is adenaturization of the very delicate proteins of the substrate and anon-uniform distribution of the gases into contact with differentportions of the carrier surfaces. The constructions having a spiralcarrier which can be rotated, provide a substantial improvement overthis other prior-art construction, because during each rotation of thespiral carrier in a housing which is not entirely filled with liquid thehorizontally arranged open inlet of the spiral tends to pump gas intothe liquid which is entrapped between the individual turns of thespiral. In other words, in this construction gas and nutrient medium areregularly brought into contact with the cell cultures which grow on thesurfaces of the spiral carrier. Air and/or other gases can be admittedinto the spaces between the convolutions of the spiral carrier onlyonce. Moreover, especially if cell cultures are to be grown on thiscarrier, only a very slow rotation of the carrier is permissible ifuniform growth of the culture is desired. This means that if forinstance only one or two rotations of the spiral carrier take place perhour, the exchange of air and/or other gas is very slow, that is thetime periods which elapse between successive contacting of all portionsof culture which grow on the surfaces of the spiral carrier with gas, isrelatively long. Particularly if an apparatus of this type is relativelylarge, there is the further disadvantage that very long carriers of aspiral nature must be utilized. Assuming, for instance, that theapparatus is to have a spiral carrier which affords 30 square meters ofculture-growing surface, then the spiral carrier must be in form of astrip-shaped member having a length of approximately 30 meters. Ofcourse, depending upon the axial length of the spiral, thecircumferential length of the strip may be shorter but in that case itswidth (its dimension in axial length of the spiral) will be greater. Inany case, these spiral carriers are then very diffic ult to clean, andcan in fact be cleaned (for subsequent removal of the tissue cells ormicro-organisms when the particular culturing operation is completed)only with the aid of complicated and expensive auxiliary equipment. Eventhe use of granular cleaning aids, which are intended to scour the cellsor micro-organisms off the surfaces of the spiral carrier when admittedinto the housing while the spiral carrier is rotated at a fast speed,does not provide for a completely effective cleaning action.

SUMMARY OF THE INVENTION It is, accordingly, a general object of thepresent invention to overcome the disadvantages of the prior art.

More particularly, it is an object of the present invention to providean improved apparatus for culturing of tissue cells and micro-organisms,which is not possessed of the aforementioned disadvantages.

Another object of the invention is to provide such an improved apparatuswhich affords the advantages of the type of apparatus outlined earlierand having a spiral carrier, but which provides for a better gasexchange per unit of time.

Another object of the invention is to provide such an improved apparatuswhich facilitates greatly the cleaning of the culture carriers.

Another object of the invention is to provide an apparatus of the typein question, wherein the cleaning of the culture carriers with the aidof granular cleaning aids is particularly facilitated.

Still an additional object of the invention is to provide such animproved apparatus wherein the inspection of the culture carriers, whichis necessary from time to time, is made much simpler than heretofore.

In keeping with these objects, and with others which will becomeapparent hereafter, one feature of the invention resides in an apparatusfor culturing of tissue cells and micro-organisms which, briefly stated,comprises a housing, a rotatable support mounted in the housing, and aplurality of culture carriers having exposed surfaces on which therespective cultures are to grow. Connecting means releasably connectsthe carriers with the support, and drive means serve to rotate thesupport.

Such an apparatus avoids the disadvantages of the prior art and meetsall of the requirements made of it, as outlined above.

The novel features which are considered as characteristic for theinvention are set forth in particular in the appended claims. Theinvention itself, however, both as to its construction and its method ofoperation, together with additional objects and advantages 3 thereof,will be best understood from the following description of specificembodiments when read in connection with the accompaning drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a somewhat diagrammaticaxial section through an apparatus according to the present invention;

FIG. 2 is a section taken on line Il-II of FIG. 1;

FIG. 3A is a plan view of one of the culture carriers in the apparatusof FIGS. 1 and 2;

FIG. 3B is an end view of the carrier in FIG. 3A, looking towards theright in that Figure;

FIG. 4 is a fragmentary section illustrating further details of theinvention; and

FIG. 5 is a fragmentary detail view, illustrating another embodiment ofthe invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now firstly to FIGS.1-3 it will be seen that the apparatus according to the presentinvention utilizes a cylindrical housing which in the illustratedembodiment is constituted by a cylinder 9 of glass or synthetic plasticmaterial. At the opposite ends of the cylinder 9 there are provided twoend covers I l which are mounted on the cylinder 9 by means oflongitudinally extending rods 10, onto free threaded ends of which thereare threaded the illustrated nuts, so that the covers l I are pressedagainst the opposite open ends of the cylinder 9. The inwardly directedsides of the covers 1 I are provided with annular grooves in whichsealing material may be located as illustrated, so that the oppositeends of the cylinder 9 extend into these grooves and engage the sealingmaterial, whereby the housing is sealed.

A support is provided in form of a hollow shaft 4 which extends axiallythrough the housing and on which there are provided two axially spacedannuli of projections 17. Successive ones of the projections 17, that iscircumferentially successive ones of them, define with one anothernarrow grooves or spaces. The carriers for the culture to be grown areidentified with reference numeral 1 and their inner longitudinal edges,that is those closest to the shaft 4, are received in these gaps orgrooves. The insertion can be made axially or radially with respect tothe shaft 4.

Each of the carriers I has two axially spaced ends, and adjacent therespective ends of the set of carriers 1 there are located end plates19. In the illustrated embodiment there is interposed a sealing member 7(here of disc-shaped configuration) between the respective end plate 19and the juxtaposed ends of the carriers 1. The carriers 1 will,incidentally, be seen to be circumferentially distributed about theperiphery of the shaft 4 (see FIG. 2) and to be curved in thecircumferential direction of the shaft 4. At the left-hand side of FIG.I the end plate 19 abuts a shoulder of the shaft 4, and at theright-hand end the end plate 19 is held in place by a nut 20 which isthreaded onto threads provided for this purpose on the shaft 4. Thus,the end plates 19 are pressed against the opposite axial ends of thecarriers 1, holding the latter in position so that they cannot slip outof the respective grooves (note the axially extending annular flange onthe outer periphery of each of the end plates 19).

It is particularly clear from FIG. I that the inner edges of thecarriers I are not directly in contact with 4 the periphery of the shaft4, but are slightly spaced from the same so that together they form anannular clearance C about the periphery of the shaft 4 (see FIG. 1),which clearance C of course communicates with the spaces between thecircumferentially adjacent carriers 1. The end plates 19 are eachprovided with apertures 3 which communicate with the clearance C andwhich also communicate with the interior of the hous- The shaft 4communicates via an inlet 12 with a source of heat exchange fluid (forheating or cooling purposes) which circulates through the shaft 4 andleaves the latter through the outlet 12'. The shaft 4 is journalled atthe left-hand end of FIG. I in an appropriate journal formed in one ofthe plates 11, and at the right-hand end in a seal 5 (of the type thatcan be maintained sterile, and which is well known from the art) throughwhich it extends to the exterior of the housing. Inlets 6 are providedfor the admission of air and/or other gas into the interior of thehousing, and a port 8 is provided through which nutrient medium can beadmitted and through which it can also be discharged.

The spacing in circumferential direction between circumferentiallyadjacent ones of the curved carriers 1 (they need of course not becurved) is identified with reference numeral 2 (see FIG. 2) and each ofthe carriers I is provided with at least one abutment 18 which in theillustrated embodiment is formed adjacent the radially outer edge of therespective carrier 1 and which abuts a circumferentially successive oneof the carriers 1. This means that the spacing in circumferentialdirection between the carriers 1, that is the dimension of the space 2,is precisely fixed. The components 4, l, 19 and 7 in effect constitute arotatable drum which is located in the interior of the housing. Thisdrum is a structural unit, not the least due to the fact that theaxially extending annular flanges at the outer peripheries of the plates19 hold the carriers 1 in place.

In operation of the apparatus thus far described, nutrient medium isadmitted through the port 8 until it completely covers the shaft 4 sothat the uppermost ones of the carriers 1 still extend out of thenutrient medium. At this time the drive composed of an electromotor 13,as well as drive belt 16 and the associated drive pulleys l4 and 15, isenergized so that the shaft 4 begins to rotate very slowly, in theillustrated embodiment in clockwise direction. Clockwise direction isassumed because in this embodiment the carriers 1 are curved incircumferential direction, and in particular in clockwise direction.During such rotation in clockwise direction the successive curvedcarriers 1 enter out of the upper space of the housing, which is notfilled with nutrient medium, into the nutrient medium which isaccommodated in the housing in the lower space thereof. During each suchentry a bubble of gas or air is entrapped between two successive ones ofthe entering carriers 1, and during the slow rotation this gas or aircan contact all parts of the facing surfaces of the neighboring orsuccessive carriers 1. In fact, the bubble continues to do so until thecarriers 1 between which it is trapped reach the lowest point in thehousing at which time the bubble can escape through one of the openings3 into the ambient nutrient medium in the housing. During the furtherrotation in an ascending sense the space between the twocircumferentially successive carriers 1 is now completely filled withnutrient medium which is replaced with new air or gas only after thesesame carriers emerge again out of the nutrient medium contents of thehousing into the upper part of the housing which is not filled with thenutrient medium. At that time air or gas can again enter between themwhereas the nutrient medium which heretofore was entrapped between themrun off through the gap C and the openings 3 back into the main body ofnutrient medium in the housing.

In FIGS. 3A and 3B I have illustrated one of the carriers 1, in planview and in end view, respectively. It will be seen how each of thecarriers -1 is curved, without requiring a detailed description.

FIG. 4 shows on an enlarged scale how the carriers 1 are mounted thereon the shaft 4, except that in this embodiment the projections 17 arereplaced with grooves 170 which are formed in the outer periphery of thecarrier 4 and extend in axial parallelism with the axis of rotation ofthe same. FIG. 4 additionally shows that in place of the curved carriers1, or in addition to them it is also possible to provide planar carriersla which can again be secured to the carrier 4 by means of the grooves17a or as in FIGS. 1-3, by means of the projections 17.

FIG. 5, finally, illustrates an additional embodiment of the inventionwhich shows that the shaft 4 can also be provided with more than onetype of connecting means. In particular, I have illustrated theprojections 17 which were described with respect to FIGS. 1-3. It isalso possible, however, to provide the grooves 170 (shown in FIG. 4, butnot in FIG. 5) or the pin-shaped projections 21 which are shown in FIG.5. The inner edges of the carriers 1 or In would be received betweencircumferentially adjacent ones of the projections 21, just as they canbe received between circumferentially adjacent ones of the projections17. Again, all three types of connecting means can be provided on oneand the same shaft 4, if desired.

Needless to say, further possibilities for releasable connecting meanswill offer themselves readily to those skilled in the art, for instanceprojections formed on the inner edges of the carriers 1 and which extendinto appropriately shaped recesses or holes in the periphery of theshaft 4, or similar projections on the shaft 4 which extend intorecesses or holes in the inner edges of the carriers 1.

It will be clear from what has been set forth above that the apparatusaccording to the present invention meets all requirements made of it, asset forth in the introductory portions of this specification, and thatit overcomes the disadvantages outlined with respect to the prior art.Moreover, the novel apparatus has further advantages, particularly withreference to the type of apparatus of the prior art which uses a spiralcarrier, especially in terms of a simple and economically advantageousmanufacture of such an apparatus. Because the individual carriers 1, ifthey are curved, are all of the same curvature, only a single apparatusis required for producing them if they are made of synthetic plastic ormetal. If, on the other hand, a spiral carrier according to the priorart is to be produced of several pieces, then the radii of curvaturenecessarily increase in radially outward direction of the spiral so thatseparate apparatus is required for producing the separate parts of whichthe carrier is to be assembled.

More important than considerations of ease and economy of manufacture,however, is the fact that the apparatus according to the presentinvention assures that even during a slow rotation of the shaft 4sufficient gas will come in contact with a relatively small surface 6area carrying the growing culture, so that a more perfect gas exchange(contact of gas and growing culture per unit time) is obtained. Also,the fact that the carriers 1 or 1a can be readily removed facilitiesgreatly their inspection and cleaning or replacement. There are manycountries, for instance, where it is required that when a job iscompleted with an apparatus of the type in question, the apparatus mustbe completely disassembled and cleaned, or where such a requirement ismade after a certain number of production cycles has been completed.Evidently, this is very readily possible in the apparatus according tothe present invention, because merely a removal of one of the plates 11and one of the plates 19 will suffice to be able to withdraw thecarriers 1 for inspection and cleaning.

Moreover, the rather simple shape of the carriers 1 or 1a makes itpossible to make them not only of synthetic plastic material or ofmetal, but also of glass. This is a material which in many instances isvastly preferred over any other type of material for culture growingbecause it has been found to be highly advantageous for this purpose,especially for the growing of monolayer cultures.

It should be pointed out that if the carriers la are planar rather thancurved, as is shown in FIG. 4, the container must not be filled withnutrient medium to quite the extent discussed earlier, to assure thatair can be properly entrapped between successive ones of the carriers 1aas they dip into and become immersed in the nutrient medium. Theconstruction of planar carriers 10 is of course particularly simple andinexpensive, especially if they are to be made of glass. An apparatusaccording to the present invention can have a very large compositesurface area on which to grow tissue cell cultures or micro-organisms,because more than one of the shafts 4 with the associated carriers 1 andother components can be accommodated in a single housing, or the housingcan be made long enough and either the carriers 1 or 10 can be made verylong or a plurality of sets of carriers 1 or In can be provided on theshafts 4 and at axially spaced locations thereof.

It will be understood that each of the elements described above, or twoor more together. may also find a useful application in other types ofconstructions differing from the types described above.

While the invention has been illustrated and described as embodied in anapparatus for culturing of tissue cells and micro-organisms, it is notintended to be limited to the details shown, since various modificationsand structural changes may be made without departing in any way from thespirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist ofthe present invention that others can by applying current knowledgereadily adapt it for various applications without omitting featuresthat, from the standpoint of prior art, fairly constitute essentialcharacteristics of the generic or specific aspects of this inventionand, therefore, such adaptations should and are intended to becomprehended within the meaning and range of equivalence of thefollowing claims.

What is claimed as new and desired to be protected by Letters Patent isset forth in the appended:

1. In an apparatus for culturing of tissue cells and micro-organisms, acombination comprising a housing; a support mounted in said housing forrotation about an axis; drive means for rotating said support about saidaxis; a plurality of elongated culture carriers circumferentially spacedfrom each other about the periphery of said support and each elongatedin a direction parallel to said axis and partly bounding with anadjacent carrier a space that is elongated lengthwise of said axis, andhaving exposed surfaces on which respective cultures are to grow, andlongitudinally spaced ends; connecting means for releasably connectingsaid carriers with said support; and a pair of end plates located at therespective ends of said carriers.

2. In an apparatus for culturing of tissue cells and micro-organisms, acombination comprising a housing; a support mounted in said housing forrotation about an axis; drive means for rotating said support about saidaxis; a plurality of elongated culture carriers circumferentially spacedfrom each other about the periphery of said support and each extendingin a direction parallel to said axis and having exposed surfaces onwhich the respective cultures are to grow, and longitudinally spacedends; connecting means for releasably connecting said carriers with saidsupport and including first connecting portions on said support, andcooperating second connecting portions on said carriers and engagingsaid first connecting portions; and a pair of end plates located at andinterposed between the respective ends of said carriers and the interiorof said housing and holding said carriers in their respective positionsrelative to said support.

3. in an apparatus for culturing of tissue cells and micro-organisms, acombination comprising a housing; a support element mounted in saidhousing for rotation about an axis; drive means for rotating saidsupport element about said axis; a plurality of elongated culturecarrier elements circumferentially spaced from each other about theperiphery of said support and each extending in a direction parallel tosaid axis and having exposed surfaces on which the respective culturesare to grow, and longitudinally spaced ends; connecting means forreleasably connecting said carrier elements with said support elementand including grooves on one of said elements and extending along saidaxis, and engaging portions on the other of said elements and receivedin the respective grooves; and a pair of end plates located at andinterposed between the respective ends of said carrier elements and theinterior of said housing and holding said carrier elements in theirrespective positions relative to said support elements.

4. A combination as defined in claim 1, wherein said carriers arestrip-shaped; and wherein said connecting 8 means comprises groovesformed in said support in substantial parallelism with the axis ofrotation of the same, said carriers being partly received in respectiveones of said grooves and projecting from the same in direction radiallyof said axis of rotation.

5. A combination as defined in claim 1, wherein said connecting meanscomprises projections provided on said support and extending insubstantial parallelism with the axis of rotation of the same, saidprojections being spaced circumferentially of said axis; and whereinsaid carriers each have a portion received between two circumferentiallysuccessive ones of said projections.

6. A combination as defined in claim 1, wherein said support has grooveswhich extend in substantial parallelism with its axis of rotation; andwherein said carriers are of curved strip-shaped configuration and eachhave a marginal portion received in one of said grooves.

7. A combination as defined in claim 1, wherein said connecting meanscomprises projections on said support, extending in substantialparallelism with the axis of rotation of the same and being spacedcircumferentially of said axis; and wherein said carriers are of curvedstrip-shaped configuration and each have a portion received between twocircumfere ntially successive ones of said projections.

8. A combination as defined in claim 1, said carriers each having anedge face adjacent to but slightly spaced from said periphery, so thatall of said edge faces define about said periphery an annular gap whichis in communication with the spaces between periphen ally adjacent onesof said carriers.

9. A combination as defined in claim 8, wherein said endplates areprovided with apertures which communicate with said annular gap.

10. A combination as defined in claim 1, said carriers each having aninner edge adjacent to, and an outer edge radially outwardly spaced fromsaid support; and,

further comprising at least one abutment portion on each of saidcarriers intermediate said edges thereof, each abutment portion being inabutment with a circumferentially adjacent carrier so as to fix thecircumferential distance between the carriers.

11. A combination as defined in claim 10, wherein said abutment portionsare provided in the region of the respective outer edges.

0 i I I

1. IN AN APPARATUS FOR CULTURING OF TISSUE CELLS AND MICROORGANISMS, ACOMBINATION COMPRISING A HOUSING; A SUPPORT MOUNTED IN SAID HOUSING FORROTATION ABOUT AN AXIS; DRIVE MEANS FOR ROTATING SAID SUPPORT ABOUT SAIDAXIS; A PLURALITY OF ELONGATED CULTURE CARRIERS CIRCUMFERENTIALLY SPACEDFROM EACH OTHER ABOUT THE PERIPHERY OF SAID SUPPORT AND EACH ELONGATEDIN A DIRECTION PARALLEL TO SAID AXIS AND PARTLY BOUNDING WITH ANADJACENT CARRIER TO SPACE THAT IS ELONGATED LENGTHWISE OF SAID AXIS, ANDHAVING EXPOSED SURFACES ON WHICH RESPECTIVE CULTURES ARE TO GROWM ANDLONGITUDINALLY SPACES ENDS; CONNECTING MEANS FOR RELEASABLY CONNECTINGSAID CARRIER WITH SAID SUPPORT; AND A PAIR OF END PLATES LOCATED AT THERESPECTIVE ENDS OF SAID CARRIERS.
 2. In an apparatus for culturing oftissue cells and micro-organisms, a combination comprising a housing; asupport mounted in said housing for rotation about an axis; drive meansfor rotating said support about said axis; a plurality of elongatedculture carriers circumferentially spaced from each other about theperiphery of said support and each extending in a direction parallel tosaid axis and having exposed surfaces on which the respective culturesare to grow, and longitudinally spaced ends; connecting means forreleasably connecting said carriers with said support and includingfirst connecting portions on said support, and cooperating secondconnecting portions on said carriers and engaging said first connectingportions; and a pair of end plates located at and interposed between therespective ends of said carriers and the interior of said housing andholding said carriers in their respective positions relative to saidsupport.
 3. In an apparatus for culturing of tissue cells andmicro-organisms, a combination comprising a housing; a support elementmounted in said housing for rotation about an axis; drive means forrotating said support element about said axis; a plurality of elongatedculture carrier elements circumferentially spaced from each other aboutthe periphery of said support and each extending in a direction parallelto said axis and having exposed surfaces on which the respectivecultures are to grow, and longitudinally spaced ends; connecting meansfor releasably connecting said carrier elements with said supportelement and including grooves on one of said elements and extendingalong said axis, and engaging portions on the other of said elements andreceived in the respective grooves; and a pair of end plates located atand interposed between the respective ends of said carrier elements andthe interior of said housing and holding said carrier elements in theirrespective positions relative to said support elements.
 4. A combinationas defined in claim 1, wherein said carriers are strip-shaped; andwherein said connecting means comprises grooves formed in said supportin substantial parallelism with the axis of rotation of the same, saidcarriers being partly received in respective ones of said grooves andprojecting from the same in direction radially of said axis of rotation.5. A combination as defined in claim 1, wherein said connecting meanscomprises projections provided on said support and extending insubstantial parallelism with the axis of rotation of the same, saidprojections being spaced circumferentially of said axis; and whereinsaid carriers each have a portion received between two circumferentiallysuccessive ones of said projections.
 6. A combination as defined inclaim 1, wherein said support has grooves which extend in substantialparallelism with its axis of rotation; and wherein said carriers are ofcurved strip-shaped configuration and each have a marginal portionreceived in one of said grooves.
 7. A combination as defined in claim 1,wherein said connecting means comprises projections on said support,extending in substantial parallelism with the axis of rotation of thesame and being spaced circumferentially of said axis; and wherein saidcarriers are of curved strip-shaped configuration and each have aportion received between two circumferentially successive ones of saidprojections.
 8. A combination as defined in claim 1, said carriers eachhaving an edge face adjacent to but slightly spaced from said periphery,so that all of said edge faces define about said periphery an annulargap which is in communication with the spaces between peripherallyadjacent ones of said carriers.
 9. A combination as defined in claim 8,wherein said endplates are provided with apertures which communicatewith said annular gap.
 10. A combination as defined in claim 1, saidcarriers each having an inner edge adjacent to, and an outer edgeradially outwardly spaced from said support; and further comprising atleast one abutment portion on each of said carriers intermediate saidedges thereof, each abutment portion being in abutment with acircumferentially adjacent carrier so as to fix the circumferentialdistance between the carriers.
 11. A combination as defined in claim 10,wherein said abutment portions are provided in the region of therespective outer edges.